The new FDA regulations highlight the importance of accuracy in the nutritional statements made on canned food labels. For example, if a label statement is made concerning the percentage of protein in the canned food, there is only a limited variation permitted from the declared percentage. Such a requirement makes can-filling uniformity especially important, both from the quality control viewpoint, and from the FDA compliance requirement. There are many methods for obtaining uniform can filling. One of such methods meters each ingredient into the can separately. This can be time consuming, and it is difficult to blend the materials in the can to insure customer appeal.
Another method of can filling blends all the materials in advance of can-filling, and then simply fills each can with the mixed ingredients in a single step operation. This type of filling requires very uniform mixing and suspension of the ingredients during can filling. This uniform suspension can be accomplished by the use of a highly viscous canning media. However, once the can is filled and sealed, the high viscosity canning media can interfere with heat penetration during heat sterilization of the canned product, and a thin, watery consistency is usually desired in many canned products, such as soups, some stews and vegetables.